Frequency stabilization of a tunable laser light source can be critical for quantitative trace gas absorption spectroscopy. Depending on the operational wavelength, a tunable laser source such as a diode lasers can typically exhibit a wavelength drift on the order of a few picometers (on the order of gigahertz) per day to fractions of picometers per day. A typical trace gas absorption linewidth can in some instances be on the order of a fraction of a nanometer to microns. Thus, drift of the laser light source can, over time, introduce critical errors in identification and quantification of trace gas analytes, particularly in gas having one or more background compounds whose absorption spectra might interfere with absorption features of a target analyte.